Cited by 327Quantum Computing Algorithms and ArchitectureQuantum Information and CryptographyQuantum Mechanics and Applications

The DOI matches its Crossref record; 27 of the 27 references it cites were found in a registry or an index; none of the 25 sources its claims cite is checked for support yet.

Experimental Demonstration of a Compiled Version of Shor’s Algorithm with Quantum Entanglement

Open access

Abstract

Shor's powerful quantum algorithm for factoring represents a major challenge in quantum computation. Here, we implement a compiled version in a photonic system. For the first time, we demonstrate the core processes, coherent control, and resultant entangled states required in a full-scale implementation. These are necessary steps on the path towards scalable quantum computing. Our results highlight that the algorithm performance is not the same as that of the underlying quantum circuit and stress the importance of developing techniques for characterizing quantum algorithms.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

The paper experimentally implements compiled order-finding circuits for Shor’s algorithm factoring \(N=15\) with \(C=2\) and \(C=4\), using photonic qubits and measurement-induced nonlinearity. It reports near-ideal algorithm outputs but substantially lower circuit/process fidelities, highlighting that algorithm performance is not the same as underlying circuit performance.

Key findings

  • The order-2 circuit gave logical probabilities \(\{P_{00},P_{10}\}=\{52,48\}\pm3\%\), and the order-4 circuit gave \(\{P_{000},P_{010},P_{100},P_{110}\}=\{27,23,24,27\}\pm2\%\); after classical processing, half the time the routines yield \(r=2\) or \(r=4\), giving factors 3 and 5.
  • Argument-register state fidelities were \(F=99.9\pm0.3\%\) for order-2 and \(F=98.5\pm0.6\%\) for order-4, with linear entropies \(SL=100\pm1\%\) and \(SL=98.1\pm0.8\%\), respectively.
  • Post-modular-exponentiation entangled states showed lower circuit performance: order-2 GHZ fidelity \(F_{\mathrm{GHZ}}=59\pm4\%\), \(SL=62\pm4\%\), witness \(W_{\mathrm{GHZ}}=-9\pm4\%\); order-4 Bell-product fidelity \(F=68\pm3\%\), \(SL=52\pm4\%\), with Bell-state tangles \(41\pm5\%\) and \(33\pm5\%\).
  • Process fidelities for the order-4 two-qubit gates were \(F_p=85\%,89\%\), giving product circuit fidelity \(F_p=80\%\), versus an algorithm success rate of \(99.7\%\); order-2 decomposed three-qubit gate process fidelities were \(78\%,90\%\), with only a non-useful bound \(F_p\ge20\%\).

Methods

  • Photonic linear-optics implementation with polarization-encoded qubits from parametric downconversion, using measurement-induced nonlinearity and nondeterministic gates with one-third success probability when fully prebiased; runs were flagged by fourfold coincidence events.
  • Compiled circuits for \(N=15\): the order-2 circuit was implemented directly, while the order-4 circuit was further compiled to a pair of cnot gates; the paper used quantum state and process tomography, with convex-optimization tomography and Monte-Carlo error estimation.
  • Analysis included measured density matrices, fidelities, linear entropies, entanglement witnesses/tangles, process \(\chi\)-matrices, and logical correlations between argument and function registers.

Limitations

  • The paper states that current experiments are not scalable, that compiled algorithms do not directly imply scalability, and that direct implementation of the order-4 six-photon circuit is currently infeasible due to low six-photon rates and nondeterministic gates.
  • It also states that full tomographic characterization becomes exponentially impractical for larger circuits, that order-2 process tomography would require at least 4096 measurements and was infeasible with their count rates, and that the three-qubit gate error bound is not useful.
  • Evident from the text: this is a small-scale, compiled demonstration for \(N=15\), not a full Shor implementation; the measured entangled states partially overlap with ideal states and show environmental decoherence, and the circuit fidelities are much lower than the algorithm success rates.

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Integrity signals

Registry

Crossref · 10.1103/physrevlett.99.250505

Cites

27 of 27 references verified0 citation errors · 0 not checkable

Statistics

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Verification

Claims the paper makes

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  • It may state two separate claims as one. 22
  • Probably not a substantial claim. 7
24 of 24
  • The authors state this as an assumption.

    Only the two-qubit gates induce error in the order-4 circuit.

    “by assuming that only these gates induce error”
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Citations

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Research works printed but not linked: 1

  1. P. Shor, 1994, Proc. 35th Ann. Symp. Found. Comp. Sci.

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Items 301–327 of 327

Metadata

Authors
Lanyon, B. P., Weinhold, T. J., Langford, N. K., Barbieri, M., James, D. F. V., Gilchrist, A., & White, A. G.
Affiliations
  • The University of Queensland (AU)
  • University of Toronto (CA)
Venue
Physical Review Letters
Published
2007-12-19
Volume
99
Issue
25
Pages
250505-250505
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
OpenAlex
W1783862658
Cited by
327
References
27
Citations by year
2026: 8 · 2025: 16 · 2024: 23 · 2023: 26 · 2022: 19 · 2021: 18 · 2020: 13 · 2019: 20 · 2018: 16 · 2017: 11 · 2016: 10 · 2015: 17 · 2014: 14 · 2013: 22 · 2012: 21
FWCI
22.88
Type
journal article
Language
en
Open access
Locations
  • Physical Review Letters (publishedVersion)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • Iris (Roma Tre University) (submittedVersion)
  • Griffith Research Online (submittedVersion)
  • arXiv (Cornell University)
Funders
Australian Research Council
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Quantum Computing Algorithms and Architecture
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Information and Cryptography
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Applications
Keywords
Shor's algorithm, quantum factoring, photonic quantum computing, quantum entanglement, coherent control, quantum circuit compilation, scalable quantum computing

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